Peck Substances of Sweet Cherries and Their Alteration during SO 2 Brining

SUMMARY— During ripening the proportion of protopectin in the cherries decreased as did the average intrinsic viscosity of the pectic material. Brining of the cherries resulted in a further decrease in the intrinsic viscosity and a conversion of protopectin and pectinic acid to the pectic acid form. The texture of the brined cherries softened with increasing maturity of the starting material. On prolonged storage in SO 2 brine the texture of the cherries softened, and the intrinsic viscosity of the pectic materials decreased. The use of brines with pH levels above and below pH 3.1‐3.5 caused a decrease in the intrinsic viscosity. A slight increase in pectic breakdown was seen when the SO 2 was raised to the 2% level. The overall effect of brining on the pectic materials of the cherries was to cause extensive de‐esterification and a decrease in the viscosity average molecular weight.